Turkish President Recep Tayyip Erdoğan urged the Turkish main opposition party, the Republican People's Party (CHP), to present evidence that he has the off-shore bank accounts on Sunday in response to CHP’s accusations.

Earlier in the month, CHP Leader Kemal Kılıcdaroğlu said that members of Erdoğan’s family and his former executive assistants allegedly have transferred millions of dollars to an off-shore company.

"If Tayyip Erdoğan has a single penny abroad, he should prove it. If proven, I will not stay in this presidential post for even one minute … In which off-shore bank does Tayyip Erdogan have an account? Prove it. If you cannot prove it, you yourself will have to quit politics. If you do, I will quit politics and my post in the presidency,” Erdoğan said.

Erdoğan’s lawyers have filed a complaint against the CHP leader on Friday and demanded a compensation for the claims.

CORRUPTION AND BRIBERY

Bribery and corruption allegations about Erdoğan and his family are particularly concentrated in energy and transportation sectors. Erdoğan appointed his son-in-law, Berat Albayrak, as Energy Minister in incumbent government. A senior government advisor is said to have confided to a journalist that Erdoğan took advantage of the privatisation of a state oil refinery, according to U.S. diplomatic documents that were leaked by Wikileaks.

In 2010, leaked cables said Erdoğan had eight accounts in Swiss banks. The classified cable, released this week by WikiLeaks, is dated Dec. 30, 2004, from then-U.S. Ambassador Eric Edelman. It says: "We have heard from two contacts that Erdogan has eight accounts in Swiss banks; his explanations that his wealth comes from the wedding presents guests gave his son and that a Turkish businessman is paying the educational expenses of all four Erdogan children in the U.S. purely altruistically are lame." Another U.S. diplomatic cable, dated Feb. 27, 2009, claimed that Erdoğan's 'friends' were benefiting from Turkey's business deals with Iran. One friend from his days at a religious school was head of a Turkish company that had entered a joint venture with Iran to develop gas and build pipelines, the memo said.

On Dec. 17, 2013, Turkish prosecutors charged gold trader Reza Zarrab with bribing Turkish ministers with ties to then-Prime Minister Recep Tayyip Erdoğan, charges which were later dropped following a switch in the prosecutorial team.

In February 2014, recordings of five telephone conversations appeared on YouTube alleged to be between Erdoğan and his son, Bilal Erdoğan. The conversations are said to have taken place Dec. 17 and 18. A heated controversy erupted after the release on YouTube of the audio recordings in which Erdoğan was reportedly heard telling his son, Bilal, to urgently get rid of tens of millions of dollars. Erdogan has claimed the recordings were a montage but the experts begged to differ.

In the alleged tapes of the Erdoğan's telephone conversations, it sounds as though the prime minister has asked his son to remove $1 billion from the homes of family members and conceal it.

Erdoğan launched a purge, which is ongoing, of the Turkish judiciary and police force to cleanse it of officials involved in the investigation. Erdoğan praised Zarrab as a philanthropist, charges were dropped and he was later awarded a prize for exporter of the year by the government.